DCEG has a long history of developing and running major cohort studies, and these form the backbone of the research portfolio in the division. Existing cohorts, including but not limited to AARP, PLCO and USRT, have been extremely productive and have generated a wealth of information about potential cancer risk factors and biological markers. In the next decade, these cohorts will reach the end of their natural lifetime due to the length of time since the baseline questionnaire, the average age of the participants, and the depletion of biological samples. There is the need, therefore, to start planning now for the next generation of cohorts that will be able to continue to address current and future hypotheses about the etiology of cancer. A working group within DCEG was formed to discuss potential settings, and Health Maintenance Organizations (HMOs) like Kaiser Permanente (KP) and the US Military were selected as some of the most promising for further exploratory work. Major advantages of HMOs and the Military are the availability of electronic medical records, a passive follow-up system that is both cost effective and highly complete, existing clinical infrastructure for specimen collection and the long-term stability of the population. Furthermore, many of the HMOs have archived tissue available and the electronic records provide extensive and reliable information on drug prescriptions, medical conditions and procedures.